/*

 * wrtarga.c

 *

 * Copyright (C) 1991-1994, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains routines to write output images in Targa format.

 *

 * These routines may need modification for non-Unix environments or

 * specialized applications.  As they stand, they assume output to

 * an ordinary stdio stream.

 *

 * Based on code contributed by Lee Daniel Crocker.

 */



#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */



#ifdef TARGA_SUPPORTED





/*

 * To support 12-bit JPEG data, we'd have to scale output down to 8 bits.

 * This is not yet implemented.

 */



#if BITS_IN_JSAMPLE != 8

  Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */

#endif



/*

 * The output buffer needs to be writable by fwrite().  On PCs, we must

 * allocate the buffer in near data space, because we are assuming small-data

 * memory model, wherein fwrite() can't reach far memory.  If you need to

 * process very wide images on a PC, you might have to compile in large-memory

 * model, or else replace fwrite() with a putc() loop --- which will be much

 * slower.

 */





/* Private version of data destination object */



typedef struct {

  struct djpeg_dest_struct pub;	/* public fields */



  char *iobuffer;		/* physical I/O buffer */

  JDIMENSION buffer_width;	/* width of one row */

} tga_dest_struct;



typedef tga_dest_struct * tga_dest_ptr;





LOCAL void

write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors)

/* Create and write a Targa header */

{

  char targaheader[18];



  /* Set unused fields of header to 0 */

  MEMZERO(targaheader, SIZEOF(targaheader));



  if (num_colors > 0) {

    targaheader[1] = 1;		/* color map type 1 */

    targaheader[5] = (char) (num_colors & 0xFF);

    targaheader[6] = (char) (num_colors >> 8);

    targaheader[7] = 24;	/* 24 bits per cmap entry */

  }



  targaheader[12] = (char) (cinfo->output_width & 0xFF);

  targaheader[13] = (char) (cinfo->output_width >> 8);

  targaheader[14] = (char) (cinfo->output_height & 0xFF);

  targaheader[15] = (char) (cinfo->output_height >> 8);

  targaheader[17] = 0x20;	/* Top-down, non-interlaced */



  if (cinfo->out_color_space == JCS_GRAYSCALE) {

    targaheader[2] = 3;		/* image type = uncompressed gray-scale */

    targaheader[16] = 8;	/* bits per pixel */

  } else {			/* must be RGB */

    if (num_colors > 0) {

      targaheader[2] = 1;	/* image type = colormapped RGB */

      targaheader[16] = 8;

    } else {

      targaheader[2] = 2;	/* image type = uncompressed RGB */

      targaheader[16] = 24;

    }

  }



  if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18)

    ERREXIT(cinfo, JERR_FILE_WRITE);

}





/*

 * Write some pixel data.

 * In this module rows_supplied will always be 1.

 */



METHODDEF void

put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

		JDIMENSION rows_supplied)

/* used for unquantized full-color output */

{

  tga_dest_ptr dest = (tga_dest_ptr) dinfo;

  register JSAMPROW inptr;

  register char * outptr;

  register JDIMENSION col;



  inptr = dest->pub.buffer[0];

  outptr = dest->iobuffer;

  for (col = cinfo->output_width; col > 0; col--) {

    outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */

    outptr[1] = (char) GETJSAMPLE(inptr[1]);

    outptr[2] = (char) GETJSAMPLE(inptr[0]);

    inptr += 3, outptr += 3;

  }

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}



METHODDEF void

put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

	       JDIMENSION rows_supplied)

/* used for grayscale OR quantized color output */

{

  tga_dest_ptr dest = (tga_dest_ptr) dinfo;

  register JSAMPROW inptr;

  register char * outptr;

  register JDIMENSION col;



  inptr = dest->pub.buffer[0];

  outptr = dest->iobuffer;

  for (col = cinfo->output_width; col > 0; col--) {

    *outptr++ = (char) GETJSAMPLE(*inptr++);

  }

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}





/*

 * Write some demapped pixel data when color quantization is in effect.

 * For Targa, this is only applied to grayscale data.

 */



METHODDEF void

put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

		   JDIMENSION rows_supplied)

{

  tga_dest_ptr dest = (tga_dest_ptr) dinfo;

  register JSAMPROW inptr;

  register char * outptr;

  register JSAMPROW color_map0 = cinfo->colormap[0];

  register JDIMENSION col;



  inptr = dest->pub.buffer[0];

  outptr = dest->iobuffer;

  for (col = cinfo->output_width; col > 0; col--) {

    *outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]);

  }

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}





/*

 * Startup: write the file header.

 */



METHODDEF void

start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)

{

  tga_dest_ptr dest = (tga_dest_ptr) dinfo;

  int num_colors, i;

  FILE *outfile;



  if (cinfo->out_color_space == JCS_GRAYSCALE) {

    /* Targa doesn't have a mapped grayscale format, so we will */

    /* demap quantized gray output.  Never emit a colormap. */

    write_header(cinfo, dinfo, 0);

    if (cinfo->quantize_colors)

      dest->pub.put_pixel_rows = put_demapped_gray;

    else

      dest->pub.put_pixel_rows = put_gray_rows;

  } else if (cinfo->out_color_space == JCS_RGB) {

    if (cinfo->quantize_colors) {

      /* We only support 8-bit colormap indexes, so only 256 colors */

      num_colors = cinfo->actual_number_of_colors;

      if (num_colors > 256)

	ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors);

      write_header(cinfo, dinfo, num_colors);

      /* Write the colormap.  Note Targa uses BGR byte order */

      outfile = dest->pub.output_file;

      for (i = 0; i < num_colors; i++) {

	putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile);

	putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile);

	putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile);

      }

      dest->pub.put_pixel_rows = put_gray_rows;

    } else {

      write_header(cinfo, dinfo, 0);

      dest->pub.put_pixel_rows = put_pixel_rows;

    }

  } else {

    ERREXIT(cinfo, JERR_TGA_COLORSPACE);

  }

}





/*

 * Finish up at the end of the file.

 */



METHODDEF void

finish_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)

{

  /* Make sure we wrote the output file OK */

  fflush(dinfo->output_file);

  if (ferror(dinfo->output_file))

    ERREXIT(cinfo, JERR_FILE_WRITE);

}





/*

 * The module selection routine for Targa format output.

 */



GLOBAL djpeg_dest_ptr

jinit_write_targa (j_decompress_ptr cinfo)

{

  tga_dest_ptr dest;



  /* Create module interface object, fill in method pointers */

  dest = (tga_dest_ptr)

      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

				  SIZEOF(tga_dest_struct));

  dest->pub.start_output = start_output_tga;

  dest->pub.finish_output = finish_output_tga;



  /* Calculate output image dimensions so we can allocate space */

  jpeg_calc_output_dimensions(cinfo);



  /* Create I/O buffer.  Note we make this near on a PC. */

  dest->buffer_width = cinfo->output_width * cinfo->output_components;

  dest->iobuffer = (char *)

    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

				(size_t) (dest->buffer_width * SIZEOF(char)));



  /* Create decompressor output buffer. */

  dest->pub.buffer = (*cinfo->mem->alloc_sarray)

    ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1);

  dest->pub.buffer_height = 1;



  return (djpeg_dest_ptr) dest;

}



#endif /* TARGA_SUPPORTED */

